Several tech buses have rerouted to use U.S. Highway 101 after someone apparently shot a pellet gun at the buses on Interstate Highway 280, damaging the buses’ windows. (Courtesy Photo courtesy Teamsters Joint Council 7)

San Francisco’s “Google buses,” a term used for various tech commuter shuttles, have been vomited on, stalled by protesters dressed like clowns and parodied as pinatas.

Now an unknown assailant apparently used a pellet gun to shoot at the windows of commuter shuttles ferrying Apple and Google employees while they traveled down Interstate Highway 280 near Woodside Road on Tuesday, prompting the shuttles to reroute to U.S. Highway 101 on Wednesday, according to California Highway Patrol.

Social media posts and reports from drivers indicate the windows were cracked by an unknown projectile while the shuttles were in motion, though the CHP did not confirm that report.

“We are not sure at this time what caused the damage, but we’re not ruling anything out,” said CHP spokesperson Officer Art Montiel.

CHP knows of five incidents Tuesday — four with shuttles ferrying Apple workers and one shuttle with Google employees.

Corporate-run commuter shuttles ferry workers from San Francisco, Oakland and throughout the Bay Area south to Silicon Valley daily. Though those regional shuttles have been targeted by protests for the tech industry’s alleged role in gentrification, there’s no indication this latest act of vandalism is a protest.

“As you know these are unmarked buses, so there’s no indication these are targeted incidents,” said Montiel, though CHP had no record of other types of vehicles being targeted.

Doug Bloch is political director of the Teamsters Joint Council 7, which represents more than 100,000 workers in Northern California. Bloch said some of the buses were driven by Teamsters for shuttle companies Loop Transportation and Compass Transportation.

“It was pellet guns,” Bloch told the San Francisco Examiner. “A couple were driven by Teamsters who were understandably scared, but no one got hurt.”

“As a union we are very concerned about the safety of our members and the passengers we drive for every day,” Bloch said.

In a social media post on Twitter that has since been taken down by the user, an apparent Apple employee distributed a photo of a cracked window and wrote, “Someone is shooting at Apple commute shuttles on 280. Explains the spontaneously shattering window on the bus today :( stay safe, all.”

That Twitter user declined to be interviewed.

Since the incident, Bloch said, Apple instructed shuttle drivers to drive along Highway 101 instead of Interstate 280. News site Mashable obtained a mass email sent to Apple employees by the “Apple Commute Team,” which Mashable said it verified.

“Due to recent incidents of broken windows along the commute route, specifically on Highway 280, we’re rerouting coaches for the time being. This change in routes could mean an additional 30-45 minutes of commute time in each direction for some riders,” the email read.

It continued, “As always, the safety of our employees is our first priority. We’re working closely with law enforcement to investigate these incidents and we’ll notify you as soon as the coaches are able to return to the regular route. Thank you for your patience and understanding.”